5TH International Congress on Technology - Engineering & Science - Kuala Lumpur - Malaysia (2018-02-01)

Early Usability Evaluation On User Centered Requirement Engineering Case Study: Web Mobile Application For Sme

Usability is an important property of software because it’s related to the ability of software in matching closely to user needs and easy to use. The usability level is relative because it’s affected by users, goals, and usage situation. The characteristic of user, their goal, and user environment have to be considered in early stage of software development. This research proposed a methodology for evaluating usability in early stage of software development. There are four activities from UCD approach that combined with four requirement engineering activities. In context of use phase, the requirement engineers get around the representative user to gather their tasks, initial mental models, preference, technical competence and their expectation about the system. Interview is used as requirement elicitation technique. The next phase is usability and functional requirement analysist and prioritization. This phase results a set of requirement describing a user’s interaction with the system. During the produce design solution phase, UI attributes of the system are defined and detail of functional requirements are defined. These User Interface (UI) requirements can be evaluated in evaluate product design phase to ensure that the usability requirements are fulfilled. Three usability measurements are selected: user satisfaction by System Usability Scale, Efficiency by Overall Relative Efficiency, and Effectiveness by Task completion rate. User satisfaction is measured from SUS metrics that fulfilled by 50 participants (14 business owner/employees and 36 costumers) after they try the prototype. The SUS score is 70.3, it’s mapped to adjective rating as Excellent. Efficiency and effectiveness evaluation involved 5 users (4 costumers and 3 laundry employees/owner). For costumer, we get 100% overall relative efficiency and task completion rate because all of the costumers able to finish the task. But, we only got 45.8% overall relative efficiency and 50% task completion rate in employee/owner’s tasks because there are some tasks that can’t be finished. The costumer that test the application is the experienced user that have different characteristics with business owner/employees. The laundry costumer usually a college student or a professional worker, so they used to interact with web mobile application and rarely find the difficulties in exploring a new system. The proposed method successfully applied in the development of web mobile applications for SMEs. It is possible to evaluate usability in the analysis phase by combining requirement engineering and user-centered design approach. Considering usability in construction of the Software Requirement Specification is performed by transforming the activity diagram model to high-fidelity prototype. The prototype is validated by referring to SRS. By getting the evaluation result in early stage of development, the problems will be detected earlier and increase the probability of product success. Keywords: usability evaluation, user-centered, requirement
Novi Setiani, Ria Monika Wulandari